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POLICY BRIEFPOLICY BRIEF

Exploring New Research on Pre-K Outcomes

Adrienne Fischer, Tom Keily and Matt Weyer

MAY 2020

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As pre-K programming increasingly garners more political

attention and funding in the states, policymakers are seeking

the most up-to-date and rigorous research to support

decision-making and creation or expansion of these programs.

High-quality pre-K has bipartisan support in part because of

the vast amount of existing research detailing positive benefits

— notably that it is of great benefit to students from low-

income families and those who are dual-language learners.

However, some research also demonstrates that positive

growth among pre-K students isn’t consistently sustained

over time. This idea is known as “convergence” or “fadeout,”

because the short-term gains of pre-K attendees may diminish

in early elementary school.

The reasons for these mixed findings vary. Some researchers

have pointed out that large-scale, public pre-K often varies in

quality from program to program, making comparisons difficult.

Others have suggested that the convergence effect may be a

function of the instruction provided in kindergarten and early

elementary grades, which often focuses heavily on improving

the skills of struggling students who may lack access to pre-K

rather than building on the skills of pre-K attendees.

This Policy Brief aims to capture and make sense of the most

recent research studies on pre-K programs and outcomes.

It does this by building upon, “Untangling the Evidence

on Preschool Effectiveness: Insights for Policymakers,” a

pioneering study by the Learning Policy Institute, to analyze

a set of research studies conducted between January 2018

and March 2020. To better understand the research findings,

reference the glossary of key terms.

44 states plus D.C. offer

state-funded pre-K

programs, which are often

seen as an important

investment in early

childhood development.

Research on the effectiveness

of pre-K programs is

generally positive, with

some findings of converging

effects, in part because there

are a lot of variables that are

hard to control for.

This new analysis of 15

research studies finds

significantly more long-

term positive outcomes

— extending beyond

kindergarten — than

converging effects.

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GLOSSARY OF KEY TERMSDUAL-LANGUAGE LEARNERS: These are children up to age 8 who are in the process of learning

English while still learning their home language.

EXECUTIVE FUNCTION: This group of skills helps an individual focus on multiple streams of

information at the same time and revise plans as necessary.

PRE-K: This includes part- and full-day educational programming for students ages 3 to 5.

PROGRAM EFFECTIVENESS (SHORT-TERM AND LONG-TERM): Short-term effectiveness is

generally defined as improvements in academic (generally literacy and math skills) and non-

academic outcomes (e.g., social and emotional skills, self-regulation) when compared with a

control group at kindergarten entry. Long-term effectiveness mirrors short-term effectiveness, but

with a focus on outcomes at the end of kindergarten and beyond.

QUALITY: There are two main indicators of quality in pre-K settings: process and structural.

Process quality refers to the “child’s day-to-day experiences in pre-K settings and includes the

social, emotional, physical and instructional aspects of children’s activities and interactions with

teachers, peers and materials that are the proximal determinants of child development.” Structural quality includes class-size maximums, child-to-teacher ratios and teacher qualifications, among

other characteristics.

RETENTION: Grade-level retention is often a metric used in pre-K effectiveness studies as a proxy

for academic and/or social and emotional readiness and/or achievement.

SPECIAL EDUCATION PLACEMENT: This is another proxy used in research studies, primarily

related to placement based on behavioral and/or developmental challenges.

What the Research SaysIn addition to the evidence of pre-K’s positive impacts on student achievement, pre-K enrollment

has also been demonstrated to provide positive generational gains, modest-to-strong returns on

investment, enhanced social and emotional learning skills, and spillover effects to students who did

not participate.

For example, in a study demonstrating generational effects, children of program participants were

found to be more likely to:

• Never be suspended from school, addicted or arrested.

• Have at least a high school diploma or some college experience.

• Be employed full-time or be self-employed.

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POLICY BRIEF

Estimates of the return on investment in pre-K range from $2 to $13

per dollar spent and strongly depend on the level of quality.

Additionally, a recent review of 33 research articles found small-to-medium effects for

development of social and emotional skills and reduction in problem behaviors. Studies have also

demonstrated spillover effects, where students ineligible to attend pre-K demonstrated benefits

from being enrolled in elementary classrooms with their pre-K attending peers.

The Education Commission of the States analysis considered a subset of 15 research studies,

published between January 2018 and March 2020, demonstrating 37 outcome effects. Each study

demonstrated at least one positive effect, and some studies also demonstrated converging effects.

This chart provides a breakdown of the outcome effects in both the short and long term. Short-

term effectiveness is generally defined as improvements in academic and non-academic outcomes

at kindergarten entry. Long-term effectiveness focuses on outcomes at the end of kindergarten

and beyond.

In the analysis, the majority of research demonstrates positive effects for those who participated in

pre-K: 70% demonstrated positive effects in the short term and long term, while 30% demonstrated

converging effects.

72% 68%

COMPARING SHORT-TERM AND LONG-TERM FINDINGS

= POSITIVE EFFECTS   = CONVERGING EFFECTS

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The analysis also looked at the number of positive and converging effects for specific content areas:

OUTCOME MEASURE EFFECTS

LITERACY

MATH

SPECIAL-EDUCATION PLACEMENT REDUCTION

RETENTION REDUCTION

ON-TIME HIGH SCHOOL GRADUATION

EXECUTIVE FUNCTION

LANGUAGE DEVELOPMENT (FOR DUAL-LANGUAGE LEARNERS)

SCIENCE

SOCIAL STUDIES

GPA

TOTAL NUMBER OF EFFECTS

= POSITIVE EFFECT  = CONVERGING EFFECT*

*INCLUDES NULL FINDINGS AND NEGATIVE EFFECTS.

The research shows positive short- and long-term effects across academic skills in reading

and math for all students and language development, specifically for dual-language learners.

Additionally, research found that pre-K contributed to reductions in grade-level retention, as well as

increases in on-time high school graduation and executive function. Also of note are several studies

that found larger short- and long-term positive effects of pre-K for low-income children and dual-

language learners.

To separate positive effects from converging effects, it is important to consider questions of

whether, how and for whom a pre-K program is effective. Because these are complex questions to

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POLICY BRIEF

investigate, researchers are looking at a variety of new methods to discover what works best and

in which environments. The following list highlights some critical areas of current consideration for

developing pre-K systems at scale.

QUALITY OF EARLY ELEMENTARY LEARNING ENVIRONMENTS. Recent research in Tennessee

showed that while pre-K students did not perform better overall than a control group in third

grade, students who attended high-quality elementary schools and were taught by highly

effective teachers in the years after pre-K performed significantly better than a control group

without pre-K.

STRATEGIC ALIGNMENT BETWEEN PRE-K AND EARLY ELEMENTARY. Studies have shown

that aligning curricula to build on the content covered in pre-K has a significant positive

effect on achievement in kindergarten, whereas pre-K without the enhanced curricula showed

convergence.

UNDERSTANDING THE ROLE OF PRE-K QUALITY. While elements of process quality — such

as teacher-child interactions and curriculum materials — are thought to have a greater effect on

student outcomes, structural quality components may also have an influence.

QUANTIFYING STUDENT OUTCOMES. While social and emotional learning and behavioral

development are harder to measure than academic skills, these soft skills are frequently linked

to later academic and career success. Studies of curricula focused on social and emotional

learning have shown promising results among low-income children, but incorporating these

skills uniformly on a large scale still presents a challenge.

Final ThoughtsState policymakers continue to prioritize pre-K programming. In the 2018-19 school year, they

invested more than $8.75 billion in state pre-K programs — a $301 million increase from the

previous year (up 3.6%). And in 2020, at least 19 governors touted early learning in their State of

the State address.

This new analysis shows positive effects for pre-K programs across all studies, with some instances

of convergence with peers in comparison groups. Emerging research suggests that sustaining

the positive effects gained by students during pre-K may be partly a function of the learning

environments that follow in the early elementary grades. In order to create learning environments

that sustain pre-K effects, policymakers can consider factors such as school and teacher quality,

exposure to challenging content, engaging home experiences and parental involvement.

Policymakers can also enable long-term, consistent, aligned and disaggregated data collection to

allow state education agencies and researchers to evaluate pre-K effects that inform future policy

decisions. As of 2018, 22 states link data across all early care and education programs (e.g., child

care and pre-K programs).

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Importantly, pre-K should not be expected to inoculate children for the rest of their educational

careers. What follows the pre-K years is also critical in providing high-quality environments that

sustain positive gains, especially in the K-3 grades.

Finally, while scaling high-quality pre-K environments will be a continual challenge, above all, safe

environments, positive classroom climates, and consistent, caring and responsive educators are

paramount to ensuring that positive effects from pre-K are developed. More comprehensive and

longitudinal data collection and evaluation can go a long way in improving states’ pre-K systems.

INTERESTED IN LEARNING MORE? To explore more state policy trends and other important context for

statewide pre-K programs, refer to Education Commission of the States’

Key Issue Page on Early Childhood Education.

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POLICY BRIEF

Research Articles Included in this Analysis (Listed by State and/or Locality)ALABAMA: “Achievement Gap Closure and Gains Associated with Alabama First Class Pre-K,”

Alabama Department of Early Childhood Education.

CHICAGO: “The Chicago School Readiness Project: Examining the Long-Term Impacts of an Early

Childhood Intervention,” PoLS One.

COLORADO: “Colorado Preschool Program Legislative Report 2020,” Colorado Department

of Education.

DENVER: “The Effects of Full-Day Pre-Kindergarten: Experimental Evidence of Impacts on

Children’s School Readiness,” Education Evaluation and Policy Analysis.

GEORGIA: “Children’s Outcomes through Second-Grade Findings from Year 4 of Georgia’s

Pre-K Longitudinal Study,” University of North Carolina at Chapel Hill, Frank Porter Graham Child

Development Institute.

GEORGIA: “Participation in Georgia’s Pre-K as a Predictor of Third-Grade Standardized Test

Scores,” Child Trends and Bright from the Start, Georgia Department of Early Care and Learning.

MIAMI: “New Benefits of Public School Pre-Kindergarten Programs: Early School Stability, Grade

Promotion and Exit from ELL Service,” Early Childhood Research Quarterly.

NATIONAL: “Estimating the Relationship Between Preschool Attendance and Kindergarten Science

Achievement: Implications for Early Science Achievement Gaps,” Education Finance and Policy.

NEW YORK CITY: “Strengthening Children’s Math Skills with Enhanced Instruction: The Impacts

of Making Pre-K Count and High 5s on Kindergarten Outcomes,” MDRC.

NORTH CAROLINA: “Effects of the North Carolina Pre-Kindergarten Program Findings Through

Pre-K of a Small-Scale RCT Study, 2017-2018 Statewide Evaluation,” University of North Carolina

at Chapel Hill, Frank Porter Graham Child Development Institute.

NORTH CAROLINA: “Long-Term Effects of Early Childhood Programs Through Eighth Grade: Do

the Effects Fade Out or Grow?,” Children and Youth Service Review.

TENNESSEE: “Effects of the Tennessee Pre-Kindergarten Program on Children’s Achievement

and Behavior Through Third Grade,” Vanderbilt University.

TULSA: “Tulsa Pre-K Alumni Are More Likely to Complete Algebra I Early,” Georgetown

University, Center for Research on Children in the United States.

UNSPECIFIED LOCATION: “Starting Early: The Benefits of Attending Early Childhood Education

Programs at Age 3,” American Educational Research Journal.

VIRGINIA: “The Effects of Public Pre-Kindergarten Attendance on First-Grade Literacy

Achievement: A District Study,” International Journal of Child Care and Educational Policy.

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About the Authors

Adrienne Fischer

As a policy analyst, Adrienne focuses on issues related to early learning. Prior to

joining Education Commission of the States, Adrienne covered education policy

issues with the National Conference of State Legislatures and earned a master’s

degree in public administration. When Adrienne is not hard at work, she can be

found enjoying the outdoors or immersed in a good book. Contact Adrienne at

afischer@ecs.org or 303.299.3600.

Tom Keily

As a policy analyst, Tom contributes to the work of the policy team on issues across

the education spectrum. Prior to joining Education Commission of the States, Tom

taught middle school in Milwaukee, Wisconsin. Tom is dedicated to providing state

policymakers with quality research that supports them in making a positive impact

on students’ lives. Contact Tom at tkeily@ecs.org or 303.299.3694.

Matt Weyer

As a senior policy analyst, Matt focuses on early learning issues. Prior to joining the

Education Commission of the States, Matt worked for over four years covering early

learning issues for the National Conference of State Legislatures, earned his

doctorate in educational leadership and policy studies from the University of

Denver and was a kindergarten teacher in a bilingual classroom for Denver Public

Schools. When Matt is not working, he can be found snowboarding or trail running in beautiful

Colorado. Contact Matt at mweyer@ecs.org or 303.299.3626.

AcknowledgmentEducation Commission of the States gives special thanks to Hanna Melnick, Abby Schachner and

Cathy Yun at the Learning Policy Institute for their support in developing this Policy Brief.